This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The YRC has developed an intuitive FRET metric, easy to use and understand. It has been applied to identify and characterize protein interactions in living yeast cells. We now test its ability to describe protein interactions in mammalian cells using recombineering technology to produce fluorescently tagged proteins. We will study the chromosome segregation machinery in mammalian cells. This machinery ensures that the genome is accurately distributed at each cell division. When errors do occur, these lead to imbalanced genomes.